x^2-x=6 Here you start by taking 6 away from both sides of the equation and you have:
x^2-x-6=6-6
x^2-x-6=0 Here you can easy factor
(x-3)(x+2)=0 first divide by x-3 and you get x+2=0 Take away 2 from both sides x+2-2=0-2=> x=-2
Now you go back to (x-3)(x+2)=0 and divide by x+2 and you get x-3=0 =>x=3
So the initial equation x^2-x=6 has two roots; they are -2 and 3